A steering apparatus for an automobile, as illustrated in FIG. 33, is constructed so that rotation of the steering wheel 1 is transmitted to an input shaft 3 of a steering gear unit 2, and as this input shaft 3 turns, the input shaft 3 pushes or pulls a pair of left and right tie rods 4, which apply a steering angle to the front wheels of the automobile. The steering wheel 1 is fastened to and supported by the rear end section of a steering shaft 5, and this steering shaft 5 is inserted in the axial direction through a cylindrical shaped steering column 6, and is supported by this steering column 6 such that it can rotate freely. The front end section of the steering shaft 5 is connected to the rear end section of an intermediate shaft 8 via a universal joint 7, and the front end section of this intermediate shaft 8 is connected to the input shaft 3 via a different universal joint 9. The intermediate shaft 8 is constructed so that the shaft can transmit torque, and can contract along its entire length due to an impact load, so that when the steering gear unit 2 is displaced in the backward direction due to a primary collision between an automobile and another automobile, that displacement is absorbed, which prevents the steering wheel 1 from displacing in the backward direction via the steering shaft 5 and hitting the body of the driver.
In this kind of steering apparatus for an automobile, in order to protect the body of the driver, this kind of steering apparatus for an automobile requires construction that that allows the steering wheel to displace in the forward direction while absorbing impact energy during a collision accident. In other words, after the primary collision in a collision accident, a secondary collision occurs when the body of the driver collides with the steering wheel 1. In order to protect the driver by lessening the impact applied to the body of the driver during this secondary collision, construction is known (refer to JP51-121929(U), JP2005-219641(A) and JP2000-6821(A)) and widely used in which an energy absorbing member, which absorbs an impact load by plastically deforming, is provided between the vehicle body and a member that supports the steering column 6 that supports the steering wheel 1 with respect to the vehicle body so that it can break away in the forward direction due to an impact load in the forward direction during a secondary collision, and displaces in the forward direction together with the steering column 6.
FIG. 34 to FIG. 36 illustrate an example of this kind of steering apparatus. A housing 10, which houses the reduction gear and the like of an electric power steering apparatus, is fastened to the front end section of a steering column 6a. A steering shaft 5a is supported on the inside of the steering column 6a such that it can only rotate freely, and a steering wheel 1 (see FIG. 33) can be fastened to the portion on the rear end section of this steering shaft 5a that protrudes from the opening on the rear end of the steering column 6a. The steering column 6a and the housing 10 are supported by a flat bracket on the vehicle side (not illustrated in the figure) that is fastened to the vehicle body so that they can break away in the forward direction due to an impact load in the forward direction.
To accomplish this, a bracket 12 on the column side that is supported in the middle section of the steering column 6a and a support bracket 13 on the housing side that is supported by the housing 10 are supported with respect to the vehicle body so that they both can break away in the forward direction due to an impact load in the forward direction. These support brackets 12, 13 both comprise installation plate sections 14a, 14b at one or two locations, and cutout sections 15a, 15b are formed in these installation plate sections 14a, 14b so that they are open on the rear end edges. With these cutout sections 15a, 15b covered, sliding plates 16a, 16b are assembled in the portions of the support brackets 12, 13 near both the left and right ends.
These sliding plates 16a, 16b are formed by bending thin metal plate such as carbon steel plate or stainless steel plate provided with a layer of a synthetic resin that slides easily, such as polyamide resin (nylon), polytetrafluoroethylene resin (PTFE) or the like on the surface into a U shape, having a top and bottom plate section that are connected by connecting plate section. Through holes for inserting bolts or studs are formed in portions of the top and bottom plate sections that are aligned with each other. With these sliding plates 16a, 16b mounted on the installation plate sections 14a, 14b, the through holes are aligned with the cutout sections 15a, 15b that are formed in these installation plate sections 14a, 14b. 
The bracket 12 on the column side and the bracket 13 on the housing side are supported by the fastening bracket 11 on the vehicle side by screwing nuts onto bolts or studs that are inserted through the cutout sections 15a, 15b in the installation plate sections 14a, 14b and the through holes in the sliding plates 16a, 16b, and tightening the nuts. During a secondary collision, the bolts or studs come out from the cutout sections 15a, 15b together with the sliding plates 16a, 16b, which allows the steering column 6a and the housing 10 to displace in the forward direction together with the brackets 12 on the column side, the bracket 13 on the housing side and the steering wheel 1.
In the example in the figures, energy absorbing members 17 are provided between these bolts or studs and the bracket 12 on the column side. As this bracket 12 on the column side displaces in the forward direction, the energy absorbing members 17 plastically deform so as to absorb the impact energy that is transmitted to the bracket 12 on the column side by way of the steering shaft 5a and steering column 6a. 
As illustrated in FIG. 36, during a secondary collision, the bolts or studs come out from the cutout sections 15a, 15b allowing the bracket 12 on the column side to displace in the forward direction from the normal state illustrated in FIG. 35, and the steering column 6a displaces in the forward direction together with the bracket 12 on the column side. When this happens, the bracket 13 on the housing side as well breaks away from the vehicle body, allowing this bracket 13 on the housing side to displace in the forward direction. As the bracket 12 on the column side displaces in the forward direction, the energy absorbing members 17 plastically deform and absorb impact energy that is transmitted to the bracket 12 on the column side via the steering shaft 5a and the steering column 6a, lessening the impact applied to the body of the driver.
In the case of the construction illustrated in FIG. 34 to FIG. 36, the bracket 12 on the column side is supported by the bracket on the vehicle side at two locations, on both the right and left side, so that it can break away in the forward direction during a secondary collision. From the aspect of stable displacement in the forward direction without causing the steering wheel 1 to tilt, it is important during a secondary collision, that the pair of left and right support sections be disengaged at the same time. However, tuning in order that these support sections disengage at the same time is affected not only by resistance such as the friction resistance and the shear resistance to the disengagement of these support sections, but unbalance on the left and right of the inertial mass of the portion that displaces in the forward direction together with the steering column 6a, so takes time and trouble.
In order to stabilize the breaking away of the steering column in the forward direction during a secondary collision, applying the construction disclosed in JP51-121929(U) can be somewhat effective. FIG. 37 to FIG. 39 illustrate the construction disclosed in this document. In the case of this construction, a locking notch 18 is formed in the center section in the width direction of a bracket 11 on the vehicle side that is fastened to and supported by the vehicle body side and that does not displace in the forward direction even during a secondary collision, and this locking notch 18 is open on the edge of the front end of the bracket 11 on the vehicle side. Moreover, a bracket 12a on the column side is such that it is able to displace in the forward direction together with a steering column 6b during a secondary collision.
Furthermore, both the left and right end sections of a locking capsule 19 that is fastened to this bracket 12a on the column side is locked in the locking notch 18. In other words, locking grooves 20 that are formed on both the left and right side surfaces of the locking capsule 19 engage with the edges on both the left and right sides of the locking notch 18. Therefore, the portions on both the left and right end sections of the locking capsule 19 that exist on the top side of the locking grooves 20 are positioned on the top side of bracket 11 on the vehicle side on both side sections of the locking notch 18. When the bracket 11 on the vehicle side and the locking capsule 19 are engaged by way of the locking grooves 20 and the edges on both sides of the locking notch 18, locking pins 22 are pressure fitted into small locking holes 21a, 21b that are formed in positions in these members 11, 20 that are aligned with each other, joining the members 11, 20 together. These locking pins 22 are made using a relatively soft material such as an aluminum alloy, synthetic resin or the like that will shear under an impact load that is applied during a secondary collision.
When an impact load is applied during a secondary collision from the steering column 6b to the locking capsule 19 by way of the bracket 12a on the column side, these locking pins 22 shear. The locking capsule 19 then comes out in the forward direction from the locking notch 18, which allows the steering column 6b to displace in the forward direction of the steering wheel 1 that is supported by this steering column 6b via the steering shaft.
In the case of the construction illustrated in FIG. 37 to FIG. 39, the engagement section between the locking capsule 19 that is fastened to the bracket 12a on the column side and the bracket 11 on the vehicle side is located at only one location in the center section in the width direction. Therefore, tuning for disengaging this engagement section and causing the steering wheel 1 to displace stably in the forward direction during a secondary collision becomes simple.
However, in the conventional construction, that shape of the bracket 11 on the vehicle side is special, so the construction of connecting and fastening this bracket 11a on the vehicle side to the vehicle body becomes complex, and the assembly height becomes high, therefore there is a problem in that design freedom of the steering apparatus is lost. Moreover, the number of parts increases, the work for processing parts, managing parts and assembling parts becomes troublesome, and the costs increase. Furthermore, the assembly height, for example, the distance from the center of the steering column 6b to the installation surface on the vehicle side becomes large, and there is a disadvantage in that performing design in order that the steering column 6b does not interfere with the knees of the driver becomes difficult.
In addition, in this kind of conventional construction, it is necessary to provide impact absorbing members between the portion of the bracket 11 on the vehicle side that does not displace during a secondary collision and the portion of the steering column 6b that displaces in the forward direction absorb impact energy by plastically deforming due to displacement in this forward direction. For example, preferably energy absorbing members such as disclosed in JP2000-6821(A) are placed in the center section in the width direction of the steering column 6b, and effectively deform plastically due to forward displacement of the steering column 6b. However, the energy absorbing members disclosed in this document are formed by using a press to punch and bend metal plate, such as steel plate, so the material cost and processing costs are both high. Moreover, it is necessary to connect and fasten the end sections of the energy absorbing members to some portion, so the assembly work is troublesome and the assembly costs are high, and thus the cost of an energy absorbing type steering column support apparatus becomes high.
Furthermore, during a secondary collision, often the case occurs in which the body of the driver collides with the steering wheel in a diagonal direction with respect to the width direction of the vehicle. In such a case, an impact load is applied to the locking capsule 19 in a forward diagonal direction with respect to the width direction of the vehicle, so the direction in which the impact load acts does not always coincide with the axial direction of the steering column 6b, and due to the portion of the impact load in the width direction, the edge of either the left or right side of the locking capsule 19 is strongly pushed toward an inner edge of the locking notch 18. Therefore, a strong friction force occurs between these edges that are strongly pressed together while the locking capsule 19 comes out in the forward direction from the locking notch 18.
When the locking capsule 19 comes out in the forward direction from the locking notch 18, the energy (load) required for this locking capsule 19 to displace in the forward direction becomes large, the larger the angle is between the direction that this locking capsule 19 is pressed and the edge of the one side that is rubbing. At the instant of a secondary collision, as the energy required for causing the locking capsule 19 to displace becomes larger, the impact that is applied to the body of the driver becomes large, which is a problem from the aspect of protecting the driver.
Furthermore, as illustrated in FIG. 33, in a typical steering apparatus for an automobile, the steering column 6b is installed in an inclined direction downward going toward the front, so when the bracket 11 on the vehicle side and the steering column 6b are parallel, this bracket 11 on the vehicle side is also installed in an inclined direction downward going toward the front. Therefore, during a secondary collision, the locking capsule 19 comes out from the locking notch 18 while displacing forward diagonally in the downward direction.
On the other hand, during a secondary collision, a load is applied from the body of the driver to the steering wheel in a direction nearly straight ahead, in other words, parallel with the road surface. Consequently, during a secondary collision, a difference occurs between the direction in which the locking capsule 19 comes out from the locking notch 18, and the direction in which the impact load that is applied to this locking capsule 19 acts. Therefore, the friction force that acts in the area of the friction between the locking capsule 19 and the bracket 11 on the vehicle side becomes large. In other words, a force in the twisting direction is applied to the area of friction between the bracket 11 on the vehicle side and the locking capsule 19, and the contact pressure at that this area of friction becomes high. As a result, a problem occurs in that at the instant that a secondary collision occurs, the energy required for causing the locking capsule 19 to displace in the forward direction becomes large, and performing tuning for protecting the driver becomes troublesome.